I have cranberry juice, orange juice, crème de mûre, dark rum, whiskey, and raspberry syrup. Give me cocktail suggestions that contain at least three of those ingredients.

With the ingredients you have on hand, it looks like you can craft a pretty tasty "Slow Swirl" or even a "Berry Blush." Let's break down why these cocktails could be a perfect fit based on what you have:

For a "Slow Swirl," you can use your dark rum, orange juice, and add in that lovely creme de mure (a type of berry liqueur, which is pretty close to fruits like those used in the cocktail). This drink combines citrusy elements with the rich notes of dark rum, complemented by the fruity sweetness of creme de mure. Although the original recipe calls for some other ingredients you might not have, this substitution should still deliver a delightful, complex flavor.

For a "Berry Blush," you already have cranberry juice, orange juice, and dark rum that you could use in place of the vodka. This cocktail is bright and fruity, with a well-balanced mix of sweetness and tanginess that is perfect for a refreshing drink option. Shaken with your ingredients, it will certainly bring out the best of the berry flavors you enjoy.

So, based on what you have, I'd suggest giving these recipes a try. They'll offer you a great balance of flavors using at least three of the ingredients you already have!